Officials: ISIS Has More Plots, More Targets in the Works; Manhunt Stepped Up for Two Bombing Suspects; Interview with Republican Congressman Adam Kinzinger of Illinois; Trump and Cruz Fight Now Involves Their Wives; U.S. Concerned Over North Korean Nuke. Aired 5- 6p ET

Aired March 24, 2016 - 17:00 ET

THIS IS A RUSH TRANSCRIPT. THIS COPY MAY NOT BE IN ITS FINAL FORM AND MAY BE UPDATED.

PAMELA BROWN, CNN ANCHOR: That's it for "THE LEAD." I'm Pamela Brown in for Jake Tapper. I turn you over to Wolf Blitzer in THE SITUATION ROOM.

[17:00:17] WOLF BLITZER, CNN ANCHOR: Happening now:

Breaking news: more attacks planned. U.S. counterterrorism officials warned that ISIS has multiple plots going in Europe. They say electronic intercepts, human intelligence and maps found in a raid suggest that targets have already been picked up.

Suspect at large. The manhunt intensifies. Police are searching for a suspect who fled after the airport bombing and another man spotted at the scene of the metro bombing. There's now a desperate race to track them down.

Americans targeted? The airport bombers struck near airline counters at a time when passengers would be checking in for flights bound for the United States. Were they going after Americans?

And terror plots linked. A captured fugitive is no longer cooperating, but new information connects the massacres in Brussels and Paris. The same ISIS bomb maker is tied to both attacks and there's now new concern that the plotters tried to obtain material for a dirty bomb.

I'm Wolf Blitzer. You're in THE SITUATION ROOM.

(MUSIC)

ANNOUNCER: This is CNN breaking news.

BLITZER: Let's get to the breaking news.

There's new concern right now that multiple ISIS plots may be in the planning stage right now with dozens of ISIS operatives at large. Counterterrorism officials say ISIS picked out possible targets after last November's Paris attacks and information found in a raided apartment includes maps of potential sites to be attacked. An urgent manhunt is stepped up as authorities now fear that two

suspects may have escaped the bloody attacks on the airport and a subway station in Brussels. Investigators had thought one suicide bomber was responsible for the catastrophic subway blast at Brussels, but surveillance video has now surfaced showing another man standing near the bomber, holding a large bag. Authorities are desperately trying to track him down.

The other suspect being hunted is the man seen wearing a hat in this airport surveillance image. He's believed to have left behind a powerful explosive before fleeing. The second of two airport suicide bombers has been identified as an ISIS bomb maker. He's also thought to have provided the bombs used in November's terrorist attacks.

The chairman of the House Foreign Committee says -- Intelligence Committee, I should say, he suspects the airport bombers may have targeted Americans, noting the proximity to airline counters and, indeed, the bombs went off during the time passengers would have been checking in for flights to the United States.

I'll speak with the Republican congressman, Adam Kinzinger. He's standing by. Our correspondents, analysts and guests, they will have full coverage of the day's top stories.

Let's begin with our Pentagon correspondent, Barbara Starr.

Barbara, the search has been stepped up, the investigation much more urgent right now. What's the latest?

BARBARA STARR, CNN PENTAGON CORRESPONDENT: Wolf, tonight, U.S. counterterrorism and intelligence officials are racing to figure out where the next threats may be coming from, racing to figure out what ISIS is up to.

(BEGIN VIDEOTAPE)

STARR (voice-over): Multiple ISIS plots in Europe on the radar, possibly linked to the Paris and Brussels networks. They are in various stages of planning. A combination of electronic intercepts, human sources and database tracking indicate several possible targets had been picked out by the ISIS operatives over the last few months.

Since the attacks earlier this week, information found in a raided apartment, including maps, indicated other potential targets had been chosen.

Across Belgium, the manhunt now on for two suspects still unidentified. This man on the right at the airport dressed in beige clothing is one. A second suspect spotted on surveillance holding a large bag at the subway blast. Not clear if he is dead or on the run.

Moments after the airport attack, a Brussels taxi driver looking for his airport worker's son captured the horrific scene.

my resignation to the prime minister, but he asked me to stay in my post given the situation we are in.

STARR: Belgian authorities still think Salah Abdeslam, tied to both the Brussels and November attacks in Paris, knows more than he may be telling.

PAUL CRUICKSHANK, CNN TERRORISM ANALYST: Investigators believe that he was on the inside of this plot, that he would have had knowledge and he would have perhaps, they believe, been one of the suicide bombers tasked with launching a much larger operation in Belgium in the weeks ahead.

[17:05:08] STARR: The bombers who have been identified, Khalid El Bakraoui who died in the attack on the subway and at the airport, his brother, Ibrahim El Bakraoui, and ISIS bombmaker Najim Laachraoui who also had ties to the November Paris attacks.

The State Department says there is no evidence Americans were targeted, but more must be done.

MARK TONER, STATE DEPARTMENT DEPUTY SPOKESMAN: We're going to continue to work with Belgium as well as other countries in Europe to better improve passenger screening, security checks, all those things that can help tighten up the net.

STARR: Even if the terrorist cell has direct links to ISIS, retaliating militarily against senior leaders responsible may be nearly impossible.

COL. CEDRIC LEIGHTON, CNN MILITARY ANALYST: What you're dealing with is they may not be in Raqqah, they may be in Libya, they may be in another European capital. They may be somewhere where we're completely not expecting them to be.

(END VIDEOTAPE)

STARR: Tonight, U.S. authorities looking at every clue worry there could be more attacks coming -- Wolf.

BLITZER: Barbara Starr, thank you.

Let's turn to our terrorism analyst, Paul Cruickshank.

Paul, why do they believe there are multiple additional ISIS plots in the works?

PAUL CRUICKSHANK, CNN TERRORISM ANALYST: Well, Wolf, there's recent intelligence that in the period after the Paris attacks, ISIS cells in Europe have identified targets moving towards some attack planning. There's also concern as our Pamela Brown has been reporting that the Brussels cell had additional tarts because there was some maps found at some of these residences that were raided in Brussels, possibly suggesting more targets. And we also know from Belgian officials, Wolf, that there were two

teams with this Brussels conspiracy. There was a first team, which composed of at least three plotters, including Salah Abdeslam and Mohammed Belkaid, the ringleader of this conspiracy, who were either arrested or killed last week in Belgium. That part of the plot was thwarted when they went into the residence that they were all hiding in and they found Kalashnikovs and they found an ISIS detonators suggesting a sort of Paris style bomb and gun attack was in the works.

But the other part of the cell, the second team they weren't able to find and that team they believe were accelerating their attack planning and worried that they were going to be apprehended by the authorities, so they moved forward with a smaller version of the same plan, which is the attack we saw play out in Brussels just a couple of days ago with that attack on the airport and the metro station.

But this is going to be a lot bigger, Wolf, indeed and they had a tremendous amount of explosive, a lot of TATP, 15 kilograms recovered in a suitcase at the bomb factory. That was just the suitcase they left behind because they weren't able to fit all this stuff into the taxi, Wolf.

BLITZER: Now that we know that multiple terror plots, ISIS plots are in the pipeline right now, it explains in part why the State Department the other day issued this extraordinary travel advisory to all Americans, among other things, saying terrorist groups continue to plan near term attacks throughout Europe, targeting sporting events, tourist sites, restaurants and transportation.

So, I assume, Paul, they have specific information about plots in the works right now. That's why they're telling Americans: be careful, maybe stay away from these locations.

CRUICKSHANK: They have all kinds of intelligence coming in. A lot of it is often fragmentary. It's difficult to verify, difficult to figure out exactly what's going on. This intelligence gathering is more an art than a science.

But taken together, the system really is blinking red right now that there is a grave concern that we could see a series of attack plans in Europe unfold. ISIS is ratcheting up its international attack planning. Even before the Paris attacks, Wolf, there was intelligence that came in, fragmentary intelligence that the external operations division of ISIS were planning an ambitious plot to hit five European cities, including Paris, including London, Berlin, population center in Belgium, and another city. Well, they have now hit two out of those five.

BLITZER: Paul Cruickshank, stand by.

I want to go to Brussels live right now. Our senior international correspondent, Clarissa Ward, is on the scene for us.

Clarissa, it seems there were a number of major intelligence failures leading up to these horrific attacks. What are you learning? [17:10:01] CLARISSA WARD, CNN SENIOR INTERNATIONAL CORRESPONDENT:

But I just want to say, here in Belgium, authorities have actually lowered the threat level today. Keep in mind we've just been hearing all this news coming from U.S. officials about all this possible intelligence about a possible future imminent attack. But here in Belgium, they have lowered the threat level from four to level three. That's the difference between an imminent attack and a serious threat of an attack.

Now, for all intents and purposes, you're still going to see a lot of military and police presence on the ground. There's still going to be security checks at airports, at train stations and public places. But really, it underscores the disconnect and the lack of communication between what intelligence officials elsewhere in the West are seeing and what intelligence officials here on the ground are seeing.

We saw another example of that today, Wolf. The family of Najim Laachraoui, he is the bomb maker, he is one of the suicide attackers at the airport. They came forward, gave a press conference today in which they said that they told the police back in 2013 when Najim Laachraoui went to Syria.

Again, unclear if officials actually digested this information, but taken in conjunction with some of those other failures we know about, one of the brothers, one of the Bakraoui brothers had been deported from Turkey. The other one had an Interpol red notice. Laachraoui also had an Interpol red notice.

And it appears that the raid that ultimately led to the capture of Salah Abdeslam was almost something of an accident, that authorities had been going in there thinking it was an empty apartment and it was only when three terrorists began firing live rounds of ammunition at them that they realized that they had stumbled upon something much deeper and much more dangerous.

So, today, unsurprisingly perhaps, Wolf, we saw the interior minister come forward offering his resignation. The prime minister actually refused and said it's an important time for Belgium to stay strong, so now is not the time for you to resign.

But we are definitely seeing a momentum building for accountability for these blunders, Wolf.

BLITZER: They need to create a commission of inquiry over there to learn from the blunders that clearly occurred to make sure it doesn't happen again.

Clarissa Ward, thanks very much.

Joining us now, Republican Congressman Adam Kinzinger of Illinois. He introduced the bill that would require the administration and future administrations for that matter to give Congress a detailed strategy to destroy ISIS and its affiliates. Congressman, thanks very much for joining us.

I'll get to that in a moment. But react, first of all, to the news we have that other -- that U.S. intelligence, law enforcement, counterterrorism officials are saying that there are other ISIS plots in Europe right now in the pipeline.

REP. ADAM KINZINGER (R), ILLINOIS: Yes, I think it's absolutely true. What we're seeing unfold is what many of us feared years ago, which is kind of these jihadist groups understanding in essence how to commit suicide bombs, understanding the psychological impact it has on the citizens and being able to do it through organizing on the dark parts of the Internet that intelligence agencies don't have the ability to read. I think it's something we need to be very concerned with and we need to obviously take them out in their home in Syria and Iraq, stay on the offensive, but give law enforcement the tools that they need.

And the other big point on it is this -- you know, there's a lot of political rhetoric right now, but we have to understand that moderate Muslims are our best allies in this fight. They're the ones that have the ability to notice if somebody at a mosque, for instance, is acting out of place or if somebody that lives next to them in the neighborhood maybe has some weird materials coming in and out of the house.

This is a time we need to be opening dialogue with the moderate Muslims in order to get the intelligence you need because you can't do it all from satellites and looking at encrypted things.

BLITZER: Information, Congressman, including maps were found early are in the week at these apartments.

How much can be learned about ISIS planning for future terror attacks based on what they found so far?

KINZINGER: You know, I think we can learn a lot in terms of their techniques, in terms of their thinking. I think we can know that if there's a spot marked on a map, for instance, and ISIS is aware that we now have that map, that's probably not where they're going to hit, but we obviously have to be very careful of that. There's a lot that can be gleaned from this.

But what's interesting and kind of my conjecture and what I think is going on is it's gone from where you used to have people that would go in and commit and suicide bombing and that was the end of the cell, to now it appears that you almost have officers or lieutenants that kind of guide the suicide bombers, walk away to save themselves. The suicide bombers explode and then these officers, if you will, will go to the next network and stiffen the spines of those guys to make sure they follow through.

So, it's a little more level of complexity than what we've seen in the last decade or two out of these terrorists.

BLITZER: You're correct. It seems like a relatively new feature. [17:15:01] Suicide bombers, they go out and kill themselves. There are these guides, these minders, or whatever you want to call them, who are there with them, they see what happened and they can use that background to plot future suicide bomb attacks. That's what you're saying, right?

KINZINGER: Yes, and you also look -- you know, it's not just suicide bombs anymore, it's guys showing up with AK-47s with military training and shooting innocent civilians. It's almost a hybrid of a straight military assault and suicide bombing and it's gotten way more complicated.

It's frightening because when a guy walks away from two suicide bombers, he doesn't just melt away into civilian life again. He goes out and maybe activates that network and now he can go as a hero that committed the first one.

So, it's this kind of perpetual suicide network that we have to be very careful about and give law enforcement the tools that they need to do, but we have to destroy this cancer in their home in Raqqah and elsewhere.

BLITZER: Congressman, stand by. We have more information coming in. The chairman of the House Intelligence Committee, he says these terrorists may have been Americans. We'll get the congressman's reaction to that, more information coming in.

We'll be right back.

(COMMERCIAL BREAK)

[17:20:40] BLITZER: We're back with the Republican Congressman Adam Kinzinger of Illinois.

Congressman, a man you know well, the chairman of the House Intelligence Committee, Devin Nunes, said it looks like Americans may have been specifically targeted in this attack given the fact that the explosion, the bombing, the suicide attack at the airport occurred near where U.S. flights were taking off for the United States. A second bomb went off near a Starbucks.

What's the information you have?

KINZINGER: Well, look, Devin Nunes, great guy and privy to way more information than me as chairman of the intelligence committee but I think it's entirely possible.

It could happen on one of two levels. One would be, you know, these attackers are sitting around their apartment and decide they want to hit the airport at a certain time because they know the American flights are leaving, or a target of opportunity. They walk into the terminal and notice this is an American flight with a lot of Americans and decide that's where they're going to execute the attack.

I think regardless of whether Americans were targeted or not, and we ought to be very concerned if they were, this is an attack and any attack like this is against Western values, against humanity I general. And this is the time when America needs to show strength of leadership, unite with our allies, moderate Muslim allies as well, and stand together to defeat this, or this is only going to continue in perpetuity and we'll be talking about the next suicide bombing soon, unfortunately.

BLITZER: We know about a dozen Americans are in hospitals right now. They were injured and there are several Americans right now, we don't know how many, but several Americans who are missing. They haven't yet identified the 31 people who were killed, so we'll wait for that information.

There's also this information coming in. Weeks after the Paris attacks back in November, it was now discovered that someone in the Belgian terror cell was keeping tabs on a nuclear researcher and could have been trying to build what's called a dirty bomb.

How can the U.S. stop ISIS from doing that?

KINZINGER: Well, look, we have to obviously control nuclear material where it exists, have good -- have good watch, good eyes on it. We have to have good radiation detection, which we do in a lot of major metropolitan areas.

This is a serious problem. All it is is taking nuclear material on a traditional bomb and it spreads that and then renders whatever area it touches unusable for hundreds of years.

This is, again, among those that understand terrorism, one of our worst fears, one of our doom's day scenarios. This is the time where we have to unleash all the resources that we have to make sure we're protecting our people, because, look, a lot of this is unrealistic until it happens. 9/11 seemed unrealistic until September 11th and we saw what unraveled.

BLITZER: Senator McCain told me yesterday that there's a chemical weapons factory in Raqqah that ISIS is controlling right now. It looks like ISIS is, even in the midst of all of the efforts to undermine it, it may be getting more powerful.

KINZINGER: Yes. I mean, look, we can roll them back in certain areas and we have and I commend the president where he's done that. But, you know, again, the perception is that they're being very successful and perception leads to reality. So, you have these folks now that are sitting around on the verge of jihadism that see ISIS is successful and are inspired to go join it.

I often say, you know, you're a Bulls fan when they're doing well and maybe not when they're not. So, this is something where dealing huge battlefield defeats to ISIS through indigenous forces -- probably my entire life we'll be engaged in this fight to some level.

BLITZER: One final question, in light of the attack in Belgium, you have introduced a bill demanding that the Obama administration detail its ISIS strategy, how to destroy ISIS. But the attack was apparently much more about missed signals by Europeans, Belgian officials, for example.

How do you fix that?

KINZINGER: Well, look, I mean, obviously, we have to hold the Europeans accountable for information sharing. I think we have an amazing ability as a country to bring allies together. So, maybe if we can have conferences or whatever they do to say how do you share information in a better way?

And again, the other thing is you have to reach out to moderate Muslims we trust in these communities to build human intelligence networks. And I think maybe sharing our ability to do that with the Europeans and crossing that information exchange may be one way to breach that. Look, this is tough, there's no doubt about it.

BLITZER: Up next, CNN has alarming information about how ISIS may be turning out dozens of specially trained bomb makers just like the killer behind the Belgium attacks.

(COMMERCIAL BREAK)

BLITZER: Our breaking news: counterterrorism officials now say multiple ISIS plots may be in the planning stage. Dozens of ISIS operatives may be at large and targets already may have been picked out.

We're also learning more about the Brussels bombings. Authorities say one of the suicide attackers was a skilled ISIS bombmaker. How many others does ISIS have?

[17:30:07] CNN's Brian Todd has been digging into this part of the story for us.

What are you learning, Brian?

BRIAN TODD, CNN CORRESPONDENT: They could have dozens of bomb makers, Wolf. Tonight the family of the man believed to be an ISIS bomb maker, one of the men who blew himself up at the Brussels airport, Najim Laachraoui, his family is condemning him tonight. Laachraoui's younger brother telling reporters the family is ashamed and had no idea this was coming.

This comes as we're getting new information tonight on how Laachraoui was trained by ISIS and new details on the gains they have made in their bomb-making program.

(BEGIN VIDEOTAPE)

TODD (voice-over): The new level of ISIS' bomb-making skill. Horrifyingly apparent in the devastation at the Brussels airport. Belgian investigators believe this man on the far left, Najim Laachraoui, blew himself up inside the terminal. A Belgian counterterrorism official tells CNN Laachraoui was an ISIS bomb maker. Officials have told CNN he was a key figure in the Paris attacks last November. Laachraoui's DNA was found in the bomb factory which produced the Paris explosives and he helped coordinate the assault.

PAUL CRUICKSHANK, CNN TERRORISM ANALYST: Investigators believe Laachraoui was on the phone with the attackers in real time in Paris, the three attack teams, the night of the attack.

TODD: CNN is told Najim Laachraoui, born in Morocco, grew up in the Schaerbeek neighborhood of Brussels and studied electromechanical engineering in college. A family attorney says none of his family had any contact with him since he went to Syria in 2013. That's where he may have first received explosive training. He's likely to have been skilled in making bombs with TATP. The volatile, deadly peroxide- based explosive believed to have been used in Brussels and Paris.

Tonight CNN has learned important new clues on how ISIS trains its bomb makers. A U.S. official tells CNN based on its use of suicide bombers and IEDs, ISIS has made significant gains in its training program. Analysts believe the terror group has dozens of operatives with those skills. So why, after investing that time and effort in training Najim Laachraoui would ISIS allow him to blow himself up?

JM BERGER, GEORGE WASHINGTON UNIVERSITY PROGRAM ON EXTREMISM: I think that ISIS has people who have been trained to make bombs in a very assembly line manner and those people are more expendable.

TODD: Experts say ISIS has not shown an ability to slip bombs past security screening and onto passenger aircraft, like al Qaeda's master bomb maker Ibrahim al-Asiri. But the Brussels attacks showed they can make more portable, smaller bombs that pack larger explosive power. And when Belgian police arrested one of ISIS' Paris plotters, they found evidence of its deadlier ambitions.

CRUICKSHANK: In his residence, they found about 10 hours of video surveillance footage of a Belgian nuclear official, somebody working at a nuclear site, raising the possibility that they were interested in either launching an attack on a nuclear facility or somehow trying to get access to a nuclear facility to get material out of it.

(END VIDEOTAPE)

TODD: What are U.S. and European counterterrorism officials doing to stop these plots? We're told the Europeans are focusing on trying to stop more ISIS fighters coming back into Europe. A U.S. law enforcement official would not give sources and methods but did say that tonight the FBI is working closely with U.S. intelligence to counter this threat -- Wolf.

BLITZER: Hope so. Brian, you also have some additional information about what this ISIS bomb maker, this guy named Laachraoui, did in Syria and how he managed to get back into Europe. What have you learned?

TODD: That's right, Wolf. According to Belgian court documents, Najim Laachraoui was in charge of receiving European jihadists when they first got to Syria. He was a pretty important figure there. We're also told by members of his family and their lawyer that Laachraoui returned to Belgium in September of last year. Belgian officials say he drove with fellow plotter Salah Abdeslam through the Hungary-Austria border at that time. They believe Laachraoui presented a fake Belgian I.D. with a fake name.

Phil, if these bombs are getting easier to make, more portable, should we expect more terror attacks?

PHIL MUDD, CNN COUNTERTERRORISM ANALYST: I think so. Remember, when we're talking about bombs in the past, we're talking about al Qaeda trying to get small bombs on something like an aircraft. The expertise to build that bomb and to add items in it that don't have metal, for example, so it can get through an airport detector, that's a lot more difficult than what we're talking about here.

Here, the expertise required a lot less. You've got thousands of European kids in Syria to train them to come back and say we don't need anything in an aircraft, we just need to wheel it in an airport. A lot easier to do, Wolf.

BLITZER: And that's exactly what they did in this case.

Evan, if this bomb maker, Laachraoui, if he could have the skills necessary to build a bomb like this and yet still become a suicide bomber and kill himself, what does that say?

EVAN PEREZ, CNN JUSTICE CORRESPONDENT: That means that ISIS believes that they have got bomb makers to spare, Wolf. It means that there's a master bomb maker, a teacher back in Syria who's churning out graduates.

[17:35:05] They're sending back -- sending them back to Europe and they believe that these guys are expendable, that there's others that are waiting in the wings to carry out attacks.

BLITZER: What does it say to you, Peter, that there were a bunch of brothers now in various terror attacks who work together to go forward? Just in Paris Salah and Ibrahim Abdeslam. They were involved. Cherif and Said Kouachi in the "Charlie Hebdo" terror attacks, in Boston the Tsarnaev brothers were involved. In this a new phenomenon we're getting, that family members, brothers in this particular case, they work together to plot?

PETER BERGEN, CNN NATIONAL SECURITY ANALYST: Not at all new. Not at all new. In fact in the 9/11 attacks, two -- there were four brothers who were part of the 19 hijackers, so we've seen this before. Now obviously there's an advantage in having brothers. Who are you going to trust more than your brother? You're not going to worry he's an informant. And of course we also saw a married couple in San Bernardino for the same reason. These people practice perfect operational security because they don't need to talk to anybody else about the plot.

BLITZER: The House Intelligence Committee chairman, Devon Nunez, and he's privy to a lot of information, he's the chairman of the committee, he says he suspects these terrorists in Brussels were targeting Americans because they went after -- one of the explosions near where flights to the United States were originating in Brussels, near a Starbucks. The Metro station was near the U.S. embassy in Brussels. There were at least a dozen Americans who were injured. Who knows how many of the 31 were Americans? They haven't released that information yet but there are a lot of Americans who are missing right now.

Do you believe that Americans were targeted?

MUDD: No, I don't buy it, Wolf. I know what you're saying because in America we believe everything is about us. If there's an American within 20 yards we're going to say it must be an American target.

This is simpler, Wolf. This is branding by ISIS to say transportation targets like we've seen attacked across Europe in the past, like we saw attacked on 9/11. Transportation targets which are not only iconic but also shut down an economy are targets that we can still beat you with 15 years after 9/11. I think this is a simpler story than going after Americans.

BLITZER: What are you hearing from your sources?

PEREZ: I think Phil is right. I think there's no indication that intelligence officials have yet that this was targeted against Americans. In fact where the bombings occurred was closer to a Brussels airlines counter, not near the U.S. carriers at all. And it appears --

BLITZER: But it was not that far from the United, the Delta, the American Airlines ticket counters.

PEREZ: That's right, Wolf, but it appears that they were targeting large crowds and at that hour there were plenty of flights, a very busy time for the airport.

BLITZER: ISIS does have a history, though, where they go into a terror attack, a suicide bombing of targeting specifics. The "Charlie Hebdo" attack, targeting the journalists there at that magazine, the Jewish supermarket, the kosher supermarket, the Jewish center in Belgium, going after Jews, for example. So they do have political targets that they go after.

BERGEN: Sure, that's true. And we still -- there's a lot we still don't know about the -- you know, the target selection. The people involved are either dead or gone. But it seems that, you know, certainly Americans were injured and you know -- by the law of averages, look, I mean, it's the center of Europe. You're going to have Americans in Brussels airport at any given moment. BLITZER: But we do know, Paul Cruickshank told us that the terrorists

who blew up that theater where that American rock band was performing, they asked as they were going in, where's the American band, where's the American band?

BERGEN: Right. And they --

BLITZER: So they specifically were looking for, quote, "an American band."

BERGEN: That is exactly right. They researched the schedule of this band. They were targeting that performance.

BLITZER: My sense is Devon Nunez, as a serious guy, the chairman of the Intelligence Committee, he does not make an assertion like that, that they may have been targeting Americans, unless people in the U.S. intelligence community or law enforcement community have told him this on some sort of classified basis or whatever. That's just my suspicion.

All right, guys, stick around, we have more to discuss.

The Belgian terror attacks are putting national security front and center in the U.S. presidential campaign, but it hasn't stopped Donald Trump and Ted Cruz from getting into an increasingly shrill fight over one another's wives.

Coming up, what caused this outburst from Senator Cruz?

(BEGIN VIDEO CLIP)

SEN. TED CRUZ (R), PRESIDENTIAL CANDIDATE: I don't get angry often. But you mess with my wife, you mess with my kids, that will do it every time.

Donald, you're a sniveling coward and leave Heidi the hell alone.

(END VIDEO CLIP)

[17:39:15]

(COMMERCIAL BREAK)

BLITZER: We're covering the breaking news. U.S. intelligence officials now saying that there are new warnings that fugitive ISIS terrorists are plotting and planning multiple new attacks in Europe.

The Belgian terror bombings have changed the focus of the presidential campaign, but in addition to talking about national security, Donald Trump and Ted Cruz, they're feuding about each other's wives.

CNN's Sunlen Serfaty is covering Ted Cruz for us. He unloaded on Donald Trump this afternoon.

has been really going after Ted Cruz's wife, bringing up her appearance and alleging that there's something in her past to spill the beans about. Well, this really set Ted Cruz off today. And tonight he is launching this very emotional, very angry pushback, essentially saying to Donald Trump back off.

CRUZ: It's not easy to tick me off. I don't get angry often, but you mess with my wife, you mess with my kids, that will do it every time.

Donald, you're a sniveling coward. Leave Heidi the hell alone.

SERFATY: That, after Trump re-tweeted this split screen image of Cruz's wife Heidi and his wife Melania, with the caption, "The images are worth a thousand words."

[17:45:08] CRUZ: Real men don't try to bully women. That's not an action of strength. That's an action of weakness. It's an action of fear. It's an action of a small and petty man who is intimidated by strong women.

SERFATY: Cruz today blasting Trump for bringing his wife into the middle of their campaign showdown.

CRUZ: Let me be absolutely clear. Our spouses and our children are off bounds. It is not acceptable for a big, loud, New York bully to attack my wife.

SERFATY: The attacks were first sparked by a Facebook ad from an anti-Trump Super PAC, not the Cruz campaign that, that used an old modeling photo of Melania Trump's wife posing nude. But Trump still insists his rival was somehow involved.

DONALD TRUMP (R), PRESIDENTIAL CANDIDATE: I thought it was disgraceful. And Ted Cruz knew about it.

SERFATY: The sharp, personal attacks eclipsing the divisions over national security, now emerging as a flash point between the 2016 candidates on both sides, in the wake of the Brussels terror attacks.

Tonight Hillary Clinton angling for a symbolic contrast, sitting down with Muslim leaders in California. The Democratic frontrunner blasting her GOP rivals for pursuing policies that she says will only sow division.

HILLARY CLINTON (D), PRESIDENTIAL CANDIDATE: Cannot allow our nation to be pitting groups of people against one another. We cannot give in to panic and fear. It's not in keeping with our values.

SERFATY: This comes as a brand new CNN-ORC poll shows if Trump and Clinton face off in the general election, 56 percent of voters believe that Clinton will win. Compared with 42-percent who think Trump will. And while Clinton also has an edge when it comes to who would be a better commander-in-chief and who is more in touch with the middle class, she and Trump are tied on the question of who is a stronger leader.

(END VIDEOTAPE)

SERFATY: And back on that Donald Trump-Ted Cruz fight today the -- the Trump campaign has called for the Cruz campaign to direct that anti-Trump Super PAC to pull the ad of Melania that's up on Facebook. Now the Cruz campaign tonight is responding. They say they have nothing to do with the ad and they have already denounced it -- Wolf.

BLITZER: All right. Sunlen, thanks very much.

Coming up, we'll have more of the breaking news we're following. U.S. sources now saying investigators are aware of multiple additional ISIS plots in the works. We're also following a new round of North Korean threats to wipe out its enemies. Is Kim Jong-Un's military perfecting the technology to do it?

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[17:52:25] BLITZER: As we follow the breaking news in the Belgium terror investigation, we're also now seeing some ominous new saber rattling coming in from Kim Jong-Un's North Korea which is threatening to turn parts of South Korea into, quote, "a sea of flames and ashes."

Our Pentagon correspondent Barbara Starr has been working her sources.

Barbara, what's are you hearing about this latest nuclear threat from North Korea?

BARBARA STARR, CNN PENTAGON CORRESPONDENT: Wolf, tonight I have to tell you most of the sources I'm talking to, analysts in the intelligence community, military officials, U.S. administration officials, express growing concern about this North Korean rhetoric. U.S. officials are telling me that they now believe it is probable in their analysis, in some analysis that North Korea has a miniaturized nuclear warhead. Not a firm conclusion but some in the intelligence community believe that he probably does have a miniaturized warhead.

Why is this so significant? If Kim Jong-Un can put a warhead, a nuclear warhead on a ballistic missile, launch it and have it hit a target thousands of miles away, this gives him the capability to pose a threat to the United States, to the Asian allies, to really upend security around the world. And this missile that he wants to put it on, at least one of the missiles, is a mobile missile so finding that launcher will be very difficult in times of war. And it's also solid fuel.

What does that mean? That means it's all fueled up, ready to go on a mobile launcher that can be running around North Korean country roads launching a nuclear warhead. That is the scenario that's had had the U.S. most worried. And tonight they believe that Kim may have achieved a significant step down that road and that's a miniaturized warhead. Whether it works right now, who knows. But they do think that in the words of one official probably he has one -- Wolf.

BLITZER: Are officials also concerned North Korea will conduct another underground nuclear test?

STARR: Extremely concerned, Wolf. There is an underground nuclear site where the North Koreans have dug some three underground tunnels that they could put test material into. One of those tunnels for a variety of engineering reasons is very available right now to the North Koreans. U.S. officials telling me they are seeing signs that North Korea may be preparing for another underground test. He wants to try making a hydrogen bomb. All of this ads up to Kim Jong-Un is very determined to go down the road of these weapons, these nuclear weapons -- Wolf.

BLITZER: All right. Barbara, thank you. Barbara Starr reporting.

Coming up, much more on the breaking news.

[17:55:02] U.S. counterterrorism officials now warning that ISIS has multiple plots going on in Europe right now. They say electronic intercepts, human intelligence, maps found in a raid suggest that the targets have already been picked out.

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BLITZER: Happening now, breaking news. More ISIS plots. Investigators tipped off to multiple terror attacks being planned right now in Europe. ISIS operatives set to be eyeing several -- several possible targets. Where might they strike next?

Expanding manhunt. The search for a second terror suspect under way tonight in Belgium and beyond. The man caught on camera only moments before the deadly subway explosion. Are there even more suspects at large?

Aimed at Americans? Growing suspicion the airport bombings were timed and located --